Maneuver Time Research Articles

Comprehensive Analysis of Input Shaping Techniques for a Chain Suspended from an Overhead Crane

Abstract This work investigates the use of input shaping techniques for controlling oscillations in a chain suspended from an overhead crane, aiming to enhance crane operations without sacrificing speed or safety. The study focuses on two specific input shaping strategies: step-input and polynomial-input shapers. The step-input shaper applies discrete changes at determined intervals, whereas the polynomial-input shaper utilizes a continuous function to adjust the crane's input throughout its operation. Numerical simulations assess the effectiveness of these techniques in reducing oscillations across various vibration modes of the chain and examine their impact on overall system performance metrics such as maneuver time, kinetic energy, robustness, and operational smoothness. Results from comprehensive simulations indicate that both input shapers significantly eliminated residual vibrations found in time-reduced inputs. The polynomial-input shaper demonstrated enhanced performance in decreasing the residual kinetic energy, and it promoted smoother operation and better adaptability to variations in chain length.

Early Mission Calibration Performance of NOAA-21 VIIRS Reflective Solar Bands

The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of the key instruments on the recently launched NOAA-21 (previously known as JPSS-2) satellite. The VIIRS, like its predecessors on the SNPP and NOAA-20 satellites, provides daily global coverage in 22 spectral bands from 412 nm to 12 μm. The geometrically and radiometrically calibrated observations are the basis for many operational applications and scientific research studies. A total of 14 of the 22 bands are reflective solar bands (RSBs), covering photon wavelengths from 412 nm to 2.25 μm. The RSBs were radiometrically calibrated prelaunch and have been regularly calibrated on orbit through the onboard solar diffuser (SD) and scheduled lunar observations. The on-orbit SD’s reflectance change is determined by the onboard solar diffuser stability monitor (SDSM). We review the calibration algorithms and present the early mission performance of the NASA N21 VIIRS RSBs. Using the calibration data collected at both the yaw maneuver and regular times, we derive the screen transmittance functions. The visible and near-infrared bands’ radiometric gains have been stable, nearly independent of time, and so were the radiometric gains of the shortwave-infrared bands after the second mid-mission outgassing. Further, we assess the Earth-view striping observed in the immediate prior collection (Collection 2.0) and apply a previously developed algorithm to mitigate the striping. The N21 VIIRS RSB detector signal-to-noise ratios are all above the design values with large margins. Finally, the uncertainties of the retrieved Earth-view top-of-the-atmosphere spectral reflectance factors at the respective typical spectral radiance levels are estimated to be less than 1.5% for all the RSBs, except band M11 whose reflectance factor uncertainty is 2.2%.

Evaluation of operational reliability in an electrical distribution feeder

This work analyzes the options for repowering, reconfiguration, and automatic load transfer that a feeder can have. The study was carried out from the head of a distribution substation using the CYMDIST application, through which the failure rate, repair time, and availability and unavailability indices were determined. Using the "Reliability Analysis" module of the CYMDIST software, consumer-oriented reliability indices are obtained, allowing a reconfiguration and the optimal path to be identified in a reasonable analysis time. The main results show that the repair time should be shorter than the maneuvering time for reconnection. It was also possible to define the conditions for ensuring proper operation before and after the fault, the location of the automatic reconnection equipment, and the communication system used.

Epley Maneuver Skills in Primary Care: 3D Semicircular Canal Models for Self-Learning.

Posterior canal-type benign paroxysmal positional vertigo (BPPV) is commonly treated using the Epley maneuver; however, the maneuver's use in primary care is limited by insufficient expertise. Therefore, this study aimed to evaluate the efficacy of a three-dimensional (3D) semicircular canal model as a self-learning tool for primary care physicians to improve their Epley maneuver technique. Thirty-one participants (18 family physicians, seven residents, and six medical students) performed the Dix-Hallpike maneuver on a nursing manikin, followed by the Epley maneuver on the covered 3D models before and after a 5-minute self-study period with the uncovered 3D model. We measured the number of moved beads from posterior canal into the utricle of the 3D model, time spent on the Epley maneuver, and head suspension angle of the Dix-Hallpike maneuver. Preintervention performance was divided into a skilled group (n=7) that could move almost all the beads and an unskilled group (n=24) that could move a few beads. Postintervention, the unskilled group members significantly improved their skill: The average moved beads increased from 0.35 to 8.00, maneuver time from 26.1 to 35.8 seconds, and head suspension angle from 10.3° to 16.4°. Most participants recognized the importance of correct positioning and spent adequate time. The 3D model was effective as a self-learning tool for improving Epley maneuver performance, particularly for less experienced practitioners. This approach could bridge the gap between evidence and practice in primary care for BPPV treatment, enhancing patient outcomes and reducing the need for specialist referrals.

IRON: A retrospective international multicenter study on robotic versus laparoscopic versus open approach in gallbladder cancer

ObjectiveFor patients with T1b gallbladder cancer or greater, an adequate lymphadenectomy should include at least 6 nodes. Studies comparing short- and long-term outcomes of the open approach with those of laparoscopy and robotic approaches are limited, with small sample sizes, and there are none comparing laparoscopic and robotic approaches. This study compared patients who underwent robotic, laparoscopic, and open resection of gallbladder cancer, evaluating short- and long-term outcomes. MethodsWe conducted a multicenter retrospective study of patients with T1b gallbladder cancer or greater (excluding combined organ resection and T4) who underwent open, laparoscopic, and robotic liver resection and lymphadenectomy between January 2012 and December 2022. The 3 groups were matched in terms of patient baseline and disease characteristics based on propensity score matching, comparing robotic with open and robotic with laparoscopic groups. ResultsWe enrolled 575 patients from 37 institutions. After propensity score matching, the median number of harvested nodes was higher in the robotic group than in the open (7 vs 5; P = .0150) and laparoscopic groups (7 vs 4; P < .001). The Pringle maneuver time was shorter with robotic resection than with laparoscopy (38 vs 59 minutes; P = .0034), and the robotic group also had a lower conversion rate (3% vs 14%, respectively; P = .005) and less estimated blood loss than open and laparoscopic resections. The perioperative morbidity and mortality rates did not differ. The robotic and laparoscopic approaches were associated with faster functional recovery than the open group. In the multivariate analysis, the factors related to the retrieval of at least 6 nodes were the robotic approach over open (odds ratio, 5.1529) and over laparoscopy (odds ratio, 6.7289) and the center experience (≥20 minimally invasive liver resections/year) (odds ratio, 4.962). After a mean follow-up of 42.6 months, overall survival and disease-free survival were not different between groups. ConclusionCompared with open and laparoscopic surgeries, the robotic approach for gallbladder cancer performed in a center with appropriate experience in minimally invasive surgery can provide adequate node retrieval.

Teacher Tales: Navigating the Complex Landscape of Multiple Tasks in an Elementary School

The study aimed to target into the intricate and multifaceted world of teaching by exploring the experiences of educators a certain elementary school which is anchored on Job Demands-Resources (JD-R) model. A theoretical framework was used to understand this study. Further, the study was grounded in the phenomenological assumptions. The sample population comprised five teachers who were experiencing multiple tasks on the gathered data, the researcher made used IDI and FGD which further analyzed using the thematic content analysis. The experiences were considered important to achieve the educational continuity in line with their navigation in the complex landscape of multiple tasks. The discussion was focused on maneuvering time constraints, facing workload pressures, and handling diversity of their responsibilities. The insights were considered important to achieve the educational continuity in line with their navigation in the complex landscape of multiple tasks. The discussion was focused on performing effective multitasking and continuing professional growth. The study highlighted that elementary school teachers require strong support systems and creative solutions to tackle challenges, including easing workload, preventing burnout, recognizing the importance of multitasking, and prioritizing ongoing professional growth, all aimed at improving the quality of education. Future researchers shall examine how innovative teaching methods and technology impact teachers' workload, and analyze the influence of support systems on teachers in elementary school settings.

Convex Optimization Based Design of FIR Filters for Reference Shaping

Abstract This paper explores design of Finite Impulse Response filters for controlling underdamped systems while dealing with uncertainties in model parameters. By setting magnitude constraints in the frequency domain within a convex programming framework, it ensures that dominant resonant modes are attenuated at the end of the maneuver, high-frequency unmodeled modes are not excited, and there is no inordinate accentuation of frequencies in the passband of the filter. A mobile platform with an attached flexible beam serves as a testbed to validate the designs for rest to rest maneuvers, demonstrating how different cost functions of error between the desired and optimized magnitude response affect the filter performance. The study also examines robustness in the notch area by shifting the natural frequencies of the system by shifting a tip mass at the free end of the beam. The total energy at the final maneuver time of the first three system modes is calculated as a vibration suppression metric and is used to compare established input shapers with the proposed Finite Impulse Response filters.

Clinical impact and role of major vessels involvement in laparoscopic resection for hepatic hemangioma.

Severe bleeding remains a significant concern in laparoscopic resection for hepatic hemangioma. It is rarely reported that how the degree of major vessels involvement impacts on severe bleeding. The present study primarily aimed to analyze the impacts of the number of involved major vessels (NIMV) during laparoscopic surgery for hepatic hemangioma and evaluate the risk factors associated with increased bleeding. A database search was carried out for consecutive patients who underwent laparoscopic resection for liver hemangiomas at our department from January 2018 to December 2023. The collected data included demographics, characteristics of the hemangiomas, laboratory data, operation method, surgical and postoperative variables. A total of 72 patients were enrolled in the study. 42 patients were categorized into the group with NIMV < 2, while 30 patients were divided into the group with NIMV ≥ 2. The group with NIMV ≥ 2 demonstrated a significant correlation with special segments, involved multiple segments and diameter of the hemangiomas (P < 0.01). And the perioperative variables including the extent of resection, operative time, blood loss, Pringle maneuver times, postoperative stay, drainage tube duration, and postoperative liver function (ALT, AST) also showed significant differences between the two groups (P < 0.05). Notably, NIMV ≥ 2 was identified as the most important independent risk factor for intraoperative blood loss ≥ 500ml in laparoscopic surgery for hepatic hemangioma (P = 0.011). For NIMV ≥ 2, the independent risk factor was special segments in multivariate analysis (P = 0.000). The involvement of multiple major vessels (NIMV ≥ 2) was significantly associated with special segments, resulting in increased intraoperative blood loss, operation difficulty, and delayed postoperative recovery. Moreover, it was identified as the single independent risk factor with a considerable risk for increased blood loss during laparoscopic resection for hepatic hemangioma.

Basic Computational Algorithms for Representing an Aircraft Flight (Calculation of 3D Displacement and Displaying)

This manuscript describes the computational process to calculate an airplane path and display it in a 2D and 3D coordinate system on a computer screen. The airplane movement is calculated as a function of its dynamic’s conditions according to physical and logical theory. Here, the flight is divided into maneuvers and the aircraft conditions are defined as boundary conditions. Then the aircraft position is calculated using nested loops, which execute the calculation procedure at every step time (Δt). The calculation of the aircraft displacement is obtained as a function of the aircraft speed and heading angles. The simulator was created using the C++ programming language, and each part of the algorithm was compiled independently to reduce the source code, allow easy modification, and improve the programming efficiency. Aerial navigation involves very complex phenomena to be considered for an appropriate representation; moreover, in this manuscript, the influence of the mathematical approach to properly represent the aircraft flight is described in detail. The flight simulator was successfully tested by simulating some basic theoretical flights with different maneuvers, which include stationary position, running along the way, take off, and some movements in the airspace. The maximum aircraft speed tested was 120 km/h, the maximum maneuver time was 12 min, and the space for simulation was assumed to be without obstacles. Here, the geometrical description of path and speed is analyzed according to the symmetric and asymmetric results. Finally, an analysis was conducted to evaluate the approach of the numerical methods used; after that, it was possible to confirm that precision increased as the step time was reduced. According to this analysis, no more than 500 steps are required for a good approach in the calculation of the aircraft displacement.

A time-fuel hybrid optimal guidance for micro/nano satellite’s glideslope approach

Aimed at the trajectory planning problem of micro/nano satellites’ approaching missions under multiple constraints, this paper proposes a V-bar glideslope maneuver optimization method considering both time and fuel consumption. A dual-objective trajectory optimization model is established based on the CW motion equation, considering the constraints of trajectory and impulse. The optimal solution set of the glideslope point position and maneuvering time is obtained by employing the NSGA2 algorithm. In order to reduce computational complexity, a method for simplifying trajectory optimization is proposed. By solving a constrained dual-impulse optimization problem, the feasible range of distance and transfer time between adjacent glideslope points are obtained, which transforms the constraint equations of the glideslope maneuver optimization into the search space of optimization variables. The problem is simplified to an unconstrained optimization problem. Finally, a simulation is conducted with the approaching mission of a typical micro/nano satellite. The results demonstrate that the proposed method can provide an optimal solution set considering both fuel and time consumption, offering a flexible maneuver planning strategy for on-orbit application.

Simultaneously Adjusting Deployment Strategies for Mega-Constellations Using Low-Thrust Maneuvers

Deploying a constellation can be costly and inefficient. The ultimate goal is to position multiple satellites into designated orbital slots with the fewest launches and lowest energy consumption. This paper presents a method for simultaneous right ascension of the ascending node (RAAN) and argument of latitude (AOL) adjustments using continuous low thrust. Firstly, how changes in the semimajor axis and inclination affect the RAAN and the AOL is analyzed. A control method is proposed, and all satellites are sequentially placed from the injection orbit to the working orbit at specific time intervals. Because the RAAN and AOL are coupled with each other, a priority control strategy is introduced. This strategy ensures that the AOL is accurately satisfied within the time between each maneuver. Next, equations that correlate the RAAN and the AOL with the orbit inclination deviation and maneuver interval time are established. By studying the maneuver time intervals and inclination compensations, a highly accurate synchronized deployment scheme can be obtained. A simulation experiment based on the OneWeb constellation is carried out. In the simulation, 80 satellites are launched by just one rocket. By employing the proposed method, the constellation is successfully deployed. Results from the simulation verified the effectiveness of the proposed algorithm, which may be employed for rapid deployment of a mega-constellation in the future.

Autonomous Mission Planning for Spacecraft On-orbit Service Based on Hybrid Variant Particle Swarm Optimization

For the complex on-orbit service (OOS) mission planning problem, an improved hybrid variant particle swarm optimization (PSO) method was proposed to improve the fuel utilization efficiency of spacecraft. Firstly, considering the time and fuel constraints, a model for OOS mission planning under the scenario of multiple target spacecrafts is established. The Lambert orbit maneuver method is used and the problem is transformed into a large-scale hybrid nonlinear integer programming problem. Next, an improved hybrid variant PSO algorithm is designed to optimize the fuel performance cost, and its simple structure and lightweight operation facilitate autonomous planning, considering the limited computing power of the onboard computer. The hybrid algorithm is composed of discrete particle swarm optimization (DPSO) and PSO, so it has a strong ability to search for the optimal service sequence and orbit maneuver time simultaneously. Moreover, the adaptive and variant operators are used to improve the searching ability and avoid falling into local optimal solutions. Finally, simulation experiments show that the proposed method can quickly give optimal results, reducing fuel consumption effectively in the OOS mission and improving the OOS capability of the spacecraft.

Orbit Determination for Impulsively Maneuvering Spacecraft Using Modified State Transition Tensor

This paper proposes a method to accurately resolve orbit determination for a spacecraft with unknown impulsive maneuvers. The proposed method handles the unknown impulsive maneuver by incorporating the magnitude, direction, and time of the impulsive maneuver into the estimation parameter vector. First, a modified state transition tensor (STT) is proposed via orbit division and segment connection, allowing the orbit to be directly propagated under the effects of impulsive maneuver uncertainties. Then, based on the modified STT, a second-order measurement model is established with the estimation parameter vector as the input. Combining the second-order measurement model with observations, a second-order optimal solution is derived to correct the estimation parameters. The spacecraft orbit, together with the magnitude, direction, and time of the impulsive maneuver, are simultaneously estimated in an iterative framework. The performance of the proposed method is validated in a low-Earth-orbit case and a high-Earth-orbit case. Simulations show that the proposed method outperforms its linear version in terms of convergence, accuracy, and uncertainty quantification capacity. Its maneuver reconstruction and orbit estimation errors are one order of magnitude less than those of competitive methods. Moreover, the proposed method can handle severe conditions and is robust to initial guesses.

A waveform command shaping control of a double pendulum with nonzero initial conditions

AbstractIn most material handling industries, input‐ and command‐shaping techniques are extensively used to transfer objects safely. In these techniques, most of the work assumes a single‐degree‐of‐freedom system with zero initial conditions, and some of these cases are not practical. In crane systems, a crane jib cannot be positioned exactly on top of the payload at the start of transfer motion, which forces the system to start with initial angles. Furthermore, when the hook is large and/or far from the payload, the system cannot be considered a single‐degree‐of‐freedom system. Not accounting for such conditions can create unwanted oscillations at the end of the motion. In this work, a closed‐form command shaping control of a double pendulum is suggested to eliminate the residual oscillations while considering nonzero initial angles. The equation of motion is derived and then solved to find the shaper constants analytically. This shaper has a selectable maneuvering time and ensures maximum cruising velocity. Several examples are implemented numerically and experimentally to evaluate the shaper's performance. Despite the nonzero initial conditions, the results showed that the shaper can effectively eliminate all induced vibrations at the end of the maneuver.

Trajectory plan for an ultra-short distance on-orbit service based on the Gaussian pseudo-spectral method

Considering the ultra-short distance approaching plan of on-orbit service, the trajectory plan strategy based on the Gaussian pseudo-spectral method is researched. Given the target spinning, safety, fuel and maneuver factors, a model which contains a secure area as well as a prohibited area is built. Furthermore, the method to plan a safe on-orbit service trajectory and the solution based on the Gaussian pseudo-spectral method are also presented. Finally, simulations are performed to prove the validity of the plan, and analyze the influence of optimal function and maneuver time. The results demonstrate that the planned trajectory is capable of avoiding the prohibited area and finding the best trajectory in terms of the relative distance, fuel cost and maneuver time respectively.

Enhanced boxing punch impact with silicone cushioning.

Elastic cushioning materials protect human tissue from injury by absorbing impact energy and delaying its transfer. However, the potential compromise in force delivery to the hitting target remains unknown. To examine if silicone cushioning compromises punch force delivery to a hitting target, a double-blind crossover trial with 12 elite boxers was conducted following material tests. Each boxer delivered five maximal punches under two conditions: silicone-hand wrapping and gauze-hand wrapping, in counterbalanced order, with a 3-day interval between sessions. Force distribution along the Z-axis indicated the punch's intended direction, while forces along the X and Y axes represented force dissipation toward unwanted direction. The material tests (based on ASTM International, West Conshohocken, PA, USA) demonstrated substantially higher compression to disruption for silicone than gauze of similar thickness. During the punching trials, the silicon-based hand wrapping exhibited slightly higher total force production (436 ± 33 N vs. 372 ± 12 N, p < 0.001) than the gauze-based hand wrapping. Moreover, force wastage, calculated as the sum of forces along the X and Y axes vs. the total force produced in percentage, was notably lower for silicone material (2.0% wastage) compared to gauze (3.8% wastage) (p < 0.001). The use of silicone materials lengthened the contact time between the punching fist and the hitting target from 35 ms to 50 ms (p < 0.001). The elastic cushion does not compromise the force delivery of the boxing glove to the hitting target. Instead, it appears to allow for additional maneuvering time for alignment during the fist-target contact with higher impact.

Safety and Survival Outcomes of Liver Resection following Triple Combination Conversion Therapy for Initially Unresectable Hepatocellular Carcinoma.

Triple combination conversion therapy, involving transcatheter arterial chemoembolization (TACE) or hepatic arterial infusion chemotherapy (HAIC) combined with tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs), has shown an encouraging objective response rate (ORR) and successful conversion surgery rate in initially unresectable hepatocellular carcinoma (HCC). However, the safety and long-term survival outcomes of subsequent liver resection after successful conversion still remain to be validated. From February 2019 to February 2023, 726 patients were enrolled in this retrospective study (75 patients received hepatectomy after conversion therapy [CLR group], and 651 patients underwent pure hepatectomy [LR group]). Propensity score matching (PSM) was used to balance the preoperative baseline characteristics. After PSM, 68 patients in the CLR group and 124 patients in the LR group were analyzed, and all the matching variables were well-balanced. Compared with the LR group, the CLR group experienced longer Pringle maneuver time, longer operation time, and longer hospital stays. In addition, the CLR group had significantly higher incidence rates of intra-abdominal bleeding, biliary leakage, post-hepatectomy liver failure (PHLF), and Clavien-Dindo grade IIIa complications than the LR group. There were no significant statistical differences in overall survival (OS) (hazard ratio [HR] 0.724; 95% confidence interval [CI] 0.356-1.474; p = 0.374) and recurrence-free survival (RFS) (HR 1.249; 95% CI 0.807-1.934; p = 0.374) between the two groups. Liver resection following triple combination conversion therapy in initially unresectable HCC may achieve favorable survival outcomes with manageable safety profiles; presenting as a promising treatment option for initially unresectable HCC.

The efficacy and safety of pure laparoscopic liver resection for hepatocellular carcinoma in super-elderly patients over 80 years: A multicenter propensity analysis.

Very few reports have evaluated the safety of laparoscopic liver resection in super-elderly patients. We assessed the short-term outcomes of laparoscopic liver resection in patients with hepatocellular carcinoma aged ≥80 years, using propensity score matching. We retrospectively analyzed the data of 287 patients (aged ≥80 years) who underwent liver resection for hepatocellular carcinoma at eight hospitals belonging to Hiroshima Surgical study group of Clinical Oncology, between January 2012 and December 2021. The perioperative outcomes were compared between laparoscopic and open liver resection, using propensity score matching. Of the 287 patients, 83 and 204 were included in the laparoscopic and open liver resection groups, respectively. Propensity score matching was performed, and 52 patients were included in each group. The operation (p = .68) and pringle maneuver (p = .11) time were not different between the groups. There were no significant differences in the incidences of bile leakage or organ failure. The laparoscopic liver resection group had significantly less intraoperative bleeding and a lower incidence of cardiopulmonary complications (both p < .01). Laparoscopic liver resection can be safely performed in elderly patients aged ≥80 years.

Roadside Infrastructure Support for Urban Automated Driving

Automated driving offers excellent opportunities for ecology, economy as well as society. Especially in urban intersections, there is a considerable margin for benefits in these sectors. This work takes a structured simulation approach to find answers on the benefit of additional information about surrounding objects of automated vehicles provided by roadside ITS stations to utilize collective perception. We are using advanced sub-microscopic 3D hardware in the loop simulation framework to generate data based on which we can achieve reliable conclusions. Our simulation data set, consisting of 400 simulation iterations, suggests that automated vehicles greatly benefit from collective perception. A lack of roadside ITS station support might lead to a disruptive impact of automated vehicles on the macroscopic traffic flow of urban road networks. If roadside collective perception is introduced to the problem, maneuver time is reduced, and traffic efficiency is increased by 19.8% on average.

Technical Tips for Performing Suprahepatic Vena Cava Tumor Thrombectomy in Renal Cell Carcinoma without Using Cardiopulmonary Bypass.

Radical nephrectomy with tumor thrombectomy for advanced renal cell carcinoma is an oncologically relevant approach that can achieve long-term survival even in the presence of distant metastases. However, the surgical techniques pose significant challenges. The objective of this clinical review was to present technical recommendations for tumor thrombectomy in the vena cava to facilitate surgical treatment. Transesophageal echocardiography is required to prepare for this procedure. Cardiopulmonary bypass should be considered when the tumor thrombus has invaded the cardiac chamber and clamping is not feasible because of the inability to milk the intracardiac chamber thrombus in the caudal direction. Prior to performing a cavotomy, it is crucial to clamp the contralateral renal vein and infrarenal and suprahepatic inferior vena cava (IVC). If the suprahepatic IVC is separated from the surrounding tissue, it can be gently pulled down toward the patient's leg until the lower margin of the atrium becomes visible. Subsequently, the tumor thrombus should be carefully pulled downward to a position where it can be clamped. Implementing the Pringle maneuver to reduce blood flow from the hepatic veins to the IVC during IVC cavotomy is simpler than clamping the hepatic veins. Sequential clamping is a two-stage method of dividing thrombectomy by clamping the IVC twice, first suprahepatically and then midretrohepatically. This sequential clamping technique helps minimize hypotension status and the Pringle maneuver time compared to single clamping. Additionally, a spiral cavotomy can decrease the degree of primary closure narrowing. The oncological prognoses of patients can be improved by incorporating these technical recommendations.